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Standard library header <stdio.h> - cppreference.com

From cppreference.com

This header is part of input/output library, providing generic file operation support and supplies I/O functions that work with narrow characters.

Types

object type, capable of holding all information needed to control a C I/O stream
(typedef) [edit]
non-array complete object type, capable of uniquely specifying a position and multibyte parser state in a file
(typedef) [edit]

Predefined standard streams

expression of type FILE* associated with the input stream
expression of type FILE* associated with the output stream
expression of type FILE* associated with the error output stream
(macro constant) [edit]

Functions

File access
opens a file
(function) [edit]
open an existing stream with a different name
(function) [edit]
closes a file
(function) [edit]
synchronizes an output stream with the actual file
(function) [edit]
sets the buffer for a file stream
(function) [edit]
sets the buffer and its size for a file stream
(function) [edit]
Direct input/output
reads from a file
(function) [edit]
writes to a file
(function) [edit]
Unformatted input/output
Narrow character
gets a character from a file stream
(function) [edit]
gets a character string from a file stream
(function) [edit]
writes a character to a file stream
(function) [edit]
writes a character string to a file stream
(function) [edit]
reads a character from stdin
(function) [edit]

(removed in C11)(C11)

 reads a character string from stdin
(function) [edit]
writes a character to stdout
(function) [edit]
writes a character string to stdout
(function) [edit]
puts a character back into a file stream
(function) [edit]
Formatted input/output
Narrow character
reads formatted input from stdin, a file stream or a buffer
(function) [edit]
reads formatted input from stdin, a file stream or a buffer
using variable argument list
(function) [edit]
prints formatted output to stdout, a file stream or a buffer
(function) [edit]
prints formatted output to stdout, a file stream or a buffer
using variable argument list
(function) [edit]
File positioning
returns the current file position indicator
(function) [edit]
gets the file position indicator
(function) [edit]
moves the file position indicator to a specific location in a file
(function) [edit]
moves the file position indicator to a specific location in a file
(function) [edit]
moves the file position indicator to the beginning in a file
(function) [edit]
Error handling
clears errors
(function) [edit]
checks for the end-of-file
(function) [edit]
checks for a file error
(function) [edit]
displays a character string corresponding of the current error to stderr
(function) [edit]
Operations on files
erases a file
(function) [edit]
renames a file
(function) [edit]
returns a pointer to a temporary file
(function) [edit]
returns a unique filename
(function) [edit]

Macro constants

integer constant expression of type int and negative value
(macro constant)
maximum number of files that can be open simultaneously
(macro constant)
size needed for an array of char to hold the longest supported file name
(macro constant)
the maximum number of characters output for any (possibly negated) NaN value
(macro constant)
size of the buffer used by setbuf
(macro constant)
indicates the buffering mode (fully buffered / line buffered / unbuffered) to be set by setvbuf
(macro constant)
indicates the offset origin (beginning / current position / end) to be used by fseek
(macro constant)
maximum number of unique filenames that can be generated by tmpnam / tmpnam_s
(macro constant)
size needed for an array of char to hold the result of tmpnam / tmpnam_s
(macro constant)

Synopsis

#define __STDC_VERSION_STDIO_H__ 202311L

typedef /* see description */ FILE;
typedef /* see description */ size_t;
typedef /* see description */ FILE;
typedef /* see description */ fpos_t;

#define NULL         /* see description */
#define _IOFBF       /* see description */
#define _IOLBF       /* see description */
#define _IONBF       /* see description */
#define BUFSIZ       /* see description */
#define EOF          /* see description */
#define FOPEN_MAX    /* see description */
#define FILENAME_MAX /* see description */
#define L_tmpnam     /* see description */
#define SEEK_CUR     /* see description */
#define SEEK_END     /* see description */
#define SEEK_SET     /* see description */
#define TMP_MAX      /* see description */

#define stdin        /* see description */
#define stdout       /* see description */
#define stderr       /* see description */

#define _PRINTF_NAN_LEN_MAX /* see description */

int remove(const char* filename);
int rename(const char* old, const char* new);
FILE* tmpfile(void);
char* tmpnam(char* s);
int fclose(FILE* stream);
int fflush(FILE* stream);
FILE* fopen(const char* restrict filename, const char* restrict mode);
FILE* freopen(const char* restrict filename, const char* restrict mode,
FILE* restrict stream);
void setbuf(FILE* restrict stream, char* restrict buf);
int setvbuf(FILE* restrict stream, char* restrict buf, int mode, size_t size);
int printf(const char* restrict format, ...);
int scanf(const char* restrict format, ...);
int snprintf(char* restrict s, size_t n, const char* restrict format, ...);
int sprintf(char* restrict s, const char* restrict format, ...);
int sscanf(const char* restrict s, const char* restrict format, ...);
int vfprintf(FILE* restrict stream, const char* restrict format, va_list arg);
int vfscanf(FILE* restrict stream, const char* restrict format, va_list arg);
int vprintf(const char* restrict format, va_list arg);
int vscanf(const char* restrict format, va_list arg);
int vsnprintf(char* restrict s, size_t n, const char* restrict format, va_list arg);
int vsprintf(char* restrict s, const char* restrict format, va_list arg);
int vsscanf(const char* restrict s, const char* restrict format, va_list arg);
int fgetc(FILE* stream);
char* fgets(char* restrict s, int n, FILE* restrict stream);
int fputc(int c, FILE* stream);
int fputs(const char* restrict s, FILE* restrict stream);
int getc(FILE* stream);
int getchar(void);
int putc(int c, FILE* stream);
int putchar(int c);
int puts(const char* s);
int ungetc(int c, FILE* stream);
size_t fread(void* restrict ptr, size_t size, size_t nmemb,
FILE* restrict stream);
size_t fwrite(const void* restrict ptr, size_t size, size_t nmemb,
FILE* restrict stream);
int fgetpos(FILE* restrict stream, fpos_t* restrict pos);
int fseek(FILE* stream, long int offset, int whence);
int fsetpos(FILE* stream, const fpos_t* pos);
long int ftell(FILE* stream);
void rewind(FILE* stream);
void clearerr(FILE* stream);
int feof(FILE* stream);
int ferror(FILE* stream);
void perror(const char* s);
int fprintf(FILE* restrict stream, const char* restrict format, ...);
int fscanf(FILE* restrict stream, const char* restrict format, ...);

Only if the implementation defines __STDC_LIB_EXT1__ and additionally the user code defines __STDC_WANT_LIB_EXT1__ before any inclusion of <stdio.h>: 

#if defined(__STDC_WANT_LIB_EXT1__)

#define L_tmpnam_s /* see description */
#define TMP_MAX_S  /* see description */

typedef /* see description */ errno_t;
typedef /* see description */ rsize_t;

errno_t tmpfile_s(FILE* restrict* restrict streamptr);
errno_t tmpnam_s(char* s, rsize_t maxsize);
errno_t fopen_s(FILE* restrict* restrict streamptr,
const char* restrict filename, const char* restrict mode);
errno_t freopen_s(FILE* restrict* restrict newstreamptr,
const char* restrict filename, const char* restrict mode,
FILE* restrict stream);
int fprintf_s(FILE* restrict stream, const char* restrict format, ...);
int fscanf_s(FILE* restrict stream, const char* restrict format, ...);
int printf_s(const char* restrict format, ...);
int scanf_s(const char* restrict format, ...);
int snprintf_s(char* restrict s, rsize_t n, const char* restrict format, ...);
int sprintf_s(char* restrict s, rsize_t n, const char* restrict format, ...);
int sscanf_s(const char* restrict s, const char* restrict format, ...);
int vfprintf_s(FILE* restrict stream, const char* restrict format, va_list arg);
int vfscanf_s(FILE* restrict stream, const char* restrict format, va_list arg);
int vprintf_s(const char* restrict format, va_list arg);
int vscanf_s(const char* restrict format, va_list arg);
int vsnprintf_s(char* restrict s, rsize_t n, const char* restrict format, va_list arg);
int vsprintf_s(char* restrict s, rsize_t n, const char* restrict format, va_list arg);
int vsscanf_s(const char* restrict s, const char* restrict format, va_list arg);
char* gets_s(char* s, rsize_t n);
#endif